Fri Oct 25 2002 08:52:
Let me tell you about some trauma I suffered recently. BART stations recently added a cool device that changes a $20 bill into four $5 bills. I really like operating this machine, and sometimes I change a $20 bill even when strictly speaking I don't need to. But recently my attempt to change a $20 bill traumatized me. You see, the machine rejected my bill. But instead of rejecting it through the bill acceptor where I'd inserted the bill in the first place, like every other machine in existence that accepts bills, it spat the bill out through a previously unrevealed orifice directly underneath. Gaaah!

The reason this so traumatized me is that I had built up an internal representation of the machine whereby I fed the machine a $20 bill and it excreted (or I milked it of, if you want a less earthy metaphor) four $5 bills. I assumed that if it didn't like my $20 bill, it would discreetly vomit it back up the way, say, the BART ticket machine will. But instead, this weird alien hole in the throat opened up and my bill was expelled through that.

I'm better now, but I take from the experience this lesson: never form an internal representation of a machine! Any machine! That machine could turn on you, and on that day you will be slightly discomfited!